CONVECTIVE MODEL OF THE THERMAL FIELD IN OROGENIC REGIONS

Abstract

The model of the thermal field in the near-surface layer that we have described elsewhere uses the equations of heat transport in the zeroth-order approximation. The equations of higher-order approximations would naturally improve the results presented in the earlier papers. In the present paper we discuss the heat-transport equations of the zeroth- and first-order approximations. As a consequence, in the first-order approximation the additional heat sources described above will appear only in the lithosphere; they will appear in the mantle only in the second-order approximation, which we do not consider here. In the general three-dimensional case, a solution in Lagrangian coordinates has been presented. In the two-dimensional case we consider a particular example which qualitatively describes the process of orogeny. We assume (1) that all the thermophysical properties are constant and are the same for both layers, and (2) that the geological medium is incompressible. The analysis of the figures indicates that the total heat flow in orogenic regions generally varies in nonmonotonic fashion along the surface.